Dye-sensitized solar cells (DSCs) have been identified as a promising alternative technology for solar energy conversion when compared to conventional devices, due to the DSC’s potential for cheap commercialization while still achieving relatively high conversion efficiencies. Much research of late in this area has been focused on the use redox mediators alternative to the prototypical iodide/triiodide couple, with the goal of tuning the redox potential in order to increase the open-circuit potential, and therefore the power, of the DSC.<br/><br/>Cobalt complexes are particularly promising alternative mediators because they have smaller visible light absorption than iodide solutions, they are non-volatile and non-corrosive to metal cathodes, and their redox potentials can be synthetically tuned by altering the structures of their ligands. It should be beneficial to the field as a whole to have a library of mediators with different redox potentials. In studying cobalt complexes with novel ligands employing highly electron-withdrawing groups in order to make high-potential complexes, we have observed very low performance in DSCs. We have characterized the novel complexes and have attributed their low performance to complex instability due to ligand lability—a result which has been scantly addressed in the current literature. With this information, we can propose alternative ligand structures for the further study of high potential cobalt mediators for application in DSCs.

On the use of cobalt complexes as mediators in dye sensitized solar cells: Instability of high-potential complexes

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.